The bulk containers made of multiwalled corrugated material laminated together are well known. Similarly, closure members for such containers are also well known. Normally such closure members comprise flaps internally foldably connected to the ends of the sleeve. The flaps are intended to be folded inwardly to close the open ends of the container (sleeve). Such flaps are normally made of the same material, i.e. the multilayered material of the side walls of the sleeve and are simply extensions of the walls separated from the walls by a fold line. Thus these closures while providing a structure that may be knocked down for shipment to the customer do require a significant amount of material particularly assuming they are to close completely the open end of the sleeve. When these flaps are folded into position perpendicular to their respective side walls they inhibit deflection of the side walls by an internal load and thus have the added function of strengthening the container to resist bulging of the side walls.
It is also known to manufacture a multiwall container in the form of an open ended sleeve and to slit the sleeve adjacent its opposite ends along the fold lines connecting the adjacent wall panels to provide reinforcing rim flaps that are then folded over into face to face relationship with the outside wall panels of the container to provide a reinforcing rim encircling the periphery of the open end of the sleeve. This rim may be further reinforced by a banding member extending there around to further aid in reduction of bulging. Obviously the structure per se does not provide for very significant resistance to bulging of the side walls.
It is also known to put a capping panel over the top of the open ended sleeve having reinforcing rims as above described and to interlock flaps on the capping panel with the flaps extending from the side wall and forming the reinforcing rim so that each cap is connected by flaps to the reinforcing rim at least on one pair of opposite sides of the sleeve. Normally this structure is then held together by a suitable band extending around the rim and holding the flaps on the top panel or cap to the container or sleeve, see Canadian Pat. Nos. 576,276 issued May 19, 1959 to Welshenbach or 690,695 issued July 14, 1964 to Gile.
It will be apparent that the latter structure requires the provision of many discrete parts, i.e. a sleeve, caps, and bands to the party filling the container and party filling the container must assemble the various flaps, caps and banding material to close the container. Normally customers buying such containers do not want to be involved in maintaining an inventory of and assembling parts anymore than is absolutely essential.
Recently, multiwalled wound containers made primarily by winding multiple layers of corrugated material have been taught in U.S. Pat. No. 4,441,948 issued Apr. 10, 1984 to Gillard et al. and further refined as described in U.S. Pat. No. 4,601,407 issued July 22, 1986 to Gillard to permit folding into a substantially flattened knocked down sleeve for easy shipment.
This container has been further modified as taught in U.S. Pat. No. 4,623,072 issued Nov. 18, 1986 to Lorenz to be provided with flaps for reinforcing the end of the container when closing same. These flaps, using the particular fold line disclosed, fold into nestled relationship on the inside of the sleeve and provide an angle structure extending around the circumference of the sleeve reinforcing the walls of the sleeve to inhibit bowing under internal load.
Canadian Pat. No. 550,162 issued Dec. 17, 1957 to Dedmon (U.S. Pat. No. 2,778,523) discloses a wooden crate (wire bound) having closed flaps secured thereto adjacent the top and bottom so that the flaps may be folded over to close the end of the crate to replace the wooden panel that was normally nailed in place.